The present invention relates to novel cosmetic or dermatological compositions with film-forming properties, containing solutions of specific multiblock ionizable polycondensates, as well as to various possible uses thereof, in particular in the field of cosmetic (i.e. topical) treatment of the skin, the hair, the nails and other keratin substances.
It is common practice in cosmetic formulations, in particular in hair products (shampoos, conditioners, styling or treating lotions or gels, lacquers or lotions for shaping, setting, fixing, and the like the hair) or in make-up products (such as, for example, nail varnish, mascaras, eyeliners and the like), to use a variable proportion, depending on the nature and destination of the formulation, of at least one film-forming substance which makes it possible, or is intended to give the support on which it is applied (that is to say, here, one of the surface parts of the body, such as head hair, eyelashes, body hair, skin, nails, etc.) certain improved characteristics. Thus, for example, in the specific case of treating a head of hair, more staying power and more softness of the hair are especially sought by this technique, whereas in the more specific case of the nails, it is mainly sought to obtain a protective, shiny and hard film which adheres fully to the nails.
In order to be satisfactory in cosmetic applications, a film-forming resin needs to have certain restricting characteristics or properties, among which mention may be made more particularly, in a non-limiting manner, firstly, of a very good affinity/compatibility/harmlessness with respect to various keratin substances (skin, hair and the like), next, good film-forming properties relative to these substances (quality and uniformity of the film deposited), and, lastly, good remanence properties (adhesiveness, solidity), that is to say that it must be difficult to remove from its support by simple washing with water or using detergents (shampoos) for example. In the case of nail varnishes, the film must also have good mechanical abrasion strength. In general, it will be noted that it is often difficult in practice to find a film-forming substance which is capable of effectively satisfying several, or all, of the various cosmetic applications which may be envisaged for this substance (problem of the acceptable compromise).
In certain respects, the film-forming substances known to date, and in particular those mentioned above, are poorly suitable for obtaining compositions having good cosmetic properties, on account, in particular, of an appreciable lack of remanence, in particular of water-resistance.
Another problem lies in the fact that the films thus obtained, in particular in the context of applications of mascara or hair type, are not sufficiently shiny. This sheen is also only poorly remanent, that is to say that it disappears quickly under the action of external agents (highly water-sensitive in particular).
However, the sheen, as well as the remanence of this sheen, nowadays constitutes a particularly desired property in the field of cosmetics.
It is thus seen that there is currently a strong need in the state of the art to have available cumulating film-forming compositions, for a varied field of possible applications (hair, eyelashes, skin, nails, etc.), all the advantages generally desired or desirable in cosmetics, namely, in particular, harmlessness towards keratin substances, ease of application and of use, production of thin and uniform protective deposits, remanence of the adhesive properties, provision and remanence of sheen properties, provision of softness and lubrication, rigidity and abrasion-resistance.
In order to meet this need, it has been proposed to use mixtures of polymers which make it possible to combine all of these properties, in particular mixtures of polyorganosiloxanes (silicones) with non-silicone polymers. The reason for this is that it is known that silicones provide excellent surface properties, leading to good lubrication, good sheen and a soft feel without providing fatty substances. These polymers do not have good mechanical properties for ensuring good film-formation; they thus need to be combined with other polymers which provide mechanical properties. Polyorganopolysiloxanes, in particular polydimethylsiloxanes, are incompatible with most of the non-silicone polymers which provide mechanical properties.
To overcome these drawbacks, French patent No. 2,708,199 teaches the possibility of using a stable aqueous suspension consisting of fine, solid, generally spherical particles of polysiloxane/polyurethane and/or polyurea multiblock ionic polycondensate, these particles having been obtained by placing the said polycondensate in the pre-synthesized state in dispersion in a suitable aqueous phase. This type of dispersion of water-insoluble polymer is called a xe2x80x9cpseudo-latexxe2x80x9d. However, these pseudo-latices have certain drawbacks.
These ionizable polycondensates in aqueous suspension do not make it possible to potentiate the desired conjugation of the properties provided, on the one hand, by the silicone segments and, on the other hand, by the polyurethane and/or polyurea segments. This addivity of the properties can only be optimized if good phase separation between the silicone segments and the polyurethane and/or polyurea segments takes place during drying, such that there is, on the one hand, in the solid state, an actual stratification of the silicone segments at the surface of the matrix of the deposit consisting of the polyurethane and/or polyurea segmentsxe2x80x94it is, in fact, at the interface of this matrix with air that the specific properties of the silicones will be manifestedxe2x80x94and, on the other hand, such that the silicone segments are assembled inside the matrix of the deposit in the form of a dispersed phase.
It is very difficult to obtain, with pseudo-latices consisting of polysiloxane/polyurethane and/or polyurea ionizable polycondensates, good phase separation leading to this stratification of the silicone segments at the surface of the deposit and the formation of a silicone phase inside the deposit, and more particularly when the lengths of the polysiloxane and/or polyurethane and/or polyurea sequences are short. The result of this is that the addivity of the properties as defined above which is obtained by these pseudo-latices still remains insufficient.
Thus, after considerable research conducted in this matter, the Applicant has now found, surprisingly and unexpectedly, that it is possible to improve this phase separation substantially and consequently to potentiate the addivity of the surface properties provided by the silicones and the mechanical and/or adhesion properties provided by the polyurethanes and/or polyureas, by using solutions or emulsions of these same polysiloxane/polyurethane and/or polyurea multiblock ionizable polycondensates dissolved in an aqueous, organic or aqueous-organic solvent system.
Furthermore, the polycondensates in solution of the invention exhibit better remanence of the deposit to the action of water or of surfactant solutions (shampoos) than pseudo-latices consisting of the same polycondensates.
In accordance with the present invention, novel cosmetic compositions are therefore now proposed, which are characterized in that they comprise, in a cosmetically acceptable support, at least one solution or one emulsion of at least one multiblock polycondensate whose chain consists of the repetition of at least one polysiloxane block and of at least one polyurethane and/or polyurea block; the said polyurethane and/or polyurea block also including ionizable groups and the said polycondensate being dissolved in an aqueous, organic or aqueous-organic solvent system.
The expression xe2x80x9cionizable groupxe2x80x9d is understood to refer to any group which may be ionized by a neutralization reaction of an acidic or basic function borne by the said group, or a quaternization reaction of a tertiary amine function borne by the said group, and which may thus form an anionic, cationic, amphoteric or zwitterionic group.
The polycondensates of the invention are essentially prepared according to a two-step process. The first step consists of a standard polycondensation reaction between (i) a polysiloxane (or silicone) polymer having a hydroxyl function or an amine function at the ends of its chain (i.e. an xcex1,xcfx89-dihydroxypoly-siloxane, or an xcex1,xcfx89-diaminopolysiloxane, or an xcex1,xcfx89-aminohydroxy- or hydroxyamino-polysiloxane), and (ii) a diisocyanate (present in stoichiometric amount, or in stoichiometric excess, that is to say at more than 2 mol per mole of silicone), whereby a novel silicone is obtained, this time having an isocyanate function at each of its chain ends; then, in a second step, the chains of the polycondensate obtained above are coupled by means of a coupling agent (in variable amount chosen as a function of the desired final chain length) chosen from diols and/or diamines and/or alcoholamines, so as finally to obtain a novel polycondensate of longer chain length.
The reactions used in the first step thus lead to a polysiloxane having at its chain ends, besides the isocyanate functions mentioned above, urethane and/or urea units, according to the standard mechanisms for a condensation reaction carried out between (i) an isocyanate function, as borne by the starting diisocyanate, and (ii) an alcohol function (creation of a urethane unit in this case) or of an amine function (formation of a urea function in this case), as borne by the starting polysiloxane, namely:
xe2x80x83(polysiloxane)-OH+Oxe2x95x90Cxe2x95x90Nxe2x80x94Rxe2x80x94Nxe2x95x90Cxe2x95x90Oxe2x86x92-(polysiloxane)-Oxe2x80x94COxe2x80x94NHxe2x80x94Rxe2x80x94Nxe2x95x90Cxe2x95x90O (diisocyanate)
and/or
(polysiloxane)-NH2+Oxe2x95x90Cxe2x95x90Nxe2x80x94Rxe2x80x94Nxe2x95x90Cxe2x95x90Oxe2x86x92-(polysiloxane)-NHxe2x80x94COxe2x80x94NHxe2x80x94Rxe2x80x94Nxe2x95x90Cxe2x95x90O
The polycondensates obtained after this first step may thus effectively be defined by the general formula (1) below:
Oxe2x95x90Cxe2x95x90Nxe2x80x94Rxe2x80x94NHxe2x80x94COxe2x95x90X1-(polysiloxane)-X1xe2x80x94Oxe2x80x94NHxe2x80x94Rxe2x80x94Nxe2x95x90Cxe2x95x90Oxe2x80x83xe2x80x83(1)
in which X1 may thus represent, separately or in combination, xe2x80x94Oxe2x80x94 or xe2x80x94NHxe2x80x94.
In the second step, the alcohol and/or amine functions of the coupler (which coupler may conveniently be symbolized here by OHxe2x80x94Bxe2x80x94OH, or NH2xe2x80x94Bxe2x80x94NH2 or alternatively NH2xe2x80x94Bxe2x80x94OH) then react, according to the same mechanisms as those shown for the first step, either with the isocyanate functions borne at the end of the chain by the polysiloxane polycondensate of formula (1) above, or with isocyanate functions borne by free diisocyanate, when the latter has been introduced in stoichiometric excess during the first step, thus giving rise in the chain (longer) of the new polycondensate obtained to a sequence of urethane and/or urea units, that is to say polyurethane and/or polyurea type blocks which may be symbolized by formula (2): 
which X2 represents xe2x80x94Oxe2x80x94 or xe2x80x94NHxe2x80x94, and x is a value corresponding substantially to the number of moles of coupler used in the reaction.
As indicated above, a polycondensate consisting of the repetition of polysiloxane blocks (corresponding simply to the starting polysiloxane, and as appears in formula (1)) and polyurethane and/or polyurea blocks (formula (2)) is thus finally obtained.
According to an extremely important aspect of the invention, the couplers (that is to say, effectively, the radical B) bear ionizable groups, that is to say groups which, and respectively, when subjected to the action of a base, give anionic groups (this is the case, for example, of carboxyl groups) and when subjected to the action of an acid or quaternization, give cationic groups (the case, for example, of a tertiary amine). Neutralization of the anionizable groups (or cationizable groups respectively) with the base (or the acid respectively) may be carried out partially or completely, depending on the amounts of neutralizing agents used.
However, other characteristics, aspects and advantages of the invention will now become more apparent on reading the detailed and full description which follows, as well as the various concrete, but in no way limiting, examples intended to illustrate it.
As indicated above, the chain of the ionizable polycondensate used in the context of the present invention is essentially characterized in that it consists of the repetition (or alternation) of at least one polysiloxane type block and of at least one polyurethane and/or polyurea type block, the said polyurethane and/or polyurea blocks containing ionizable groups. Other blocks of different chemical nature may be in the chain of the polycondensate. Mention may be made, for example, of polyether blocks such as polyoxyethylene, polyoxypropylene, polytetramethylene oxide and/or polyester blocks such as poly(ethylene glycol adipate), poly(neopentyl glycol sebacate) or poly(ethylene glycol terephthalate).
The repetition of the above blocks may be of random type, but it is preferably of regularly alternating type. In addition, the numerical ratio between the polyurethane and/or polyurea type blocks and the polysiloxane type blocks is generally between 1 and 10, preferably between 1 and 3.
The molecular weights of the polysiloxane-polyurethane/polyurea polycondensates may vary within a wide range, in particular between 2000 and 500,000, but preferably between 3000 and 250,000.
Preferably, the polysiloxane block corresponds to the general formula (I) below: 
which: in
P is a polysiloxane segment,
X1 represents, separately or in combination, xe2x80x94Oxe2x80x94 or xe2x80x94NHxe2x80x94,
and R (which is none other than the diisocyanate unit as mentioned above) is a divalent radical chosen from alkylene radicals of aromatic, aliphatic or cycloaliphatic type.
Preferably, the polysiloxane segment P corresponds to the general formula (Ixe2x80x2) below: 
which the Radicals R1, which may be identical or different, are chosen, on the one hand, from monovalent C1-C20 hydrocarbon radicals which are free or substantially free of ethylenic unsaturations, and, on the other hand, aromatic radicals, Y represents a divalent hydrocarbon radical and z is an integer such that the average molecular weight of the polysiloxane segment is between 300 and 10,000.
Preferably, Y is a divalent radical chosen from alkylene radicals of formula xe2x80x94(CH2)axe2x80x94, in which a represents an integer which may be between 1 and 10.
As radicals R1 which are suitable in the context of the invention, mention may be made more particularly of alkyl radicals and, in particular, methyl, ethyl, propyl, isopropyl, butyl, pentyl, hexyl, octyl, decyl, dodecyl and octadecyl radicals, cycloalkyl radicals, in particular the cyclohexyl radical, aryl radicals, in particular phenyl and naphthyl, arylalkyl radicals, in particular benzyl and phenylethyl, and tolyl and xylyl radicals. It will be noted that, according to the invention, it is important for the polysiloxane segment to be free, or substantially free, of units of the Sixe2x80x94H or Sixe2x80x94R1 type in which R1 represents a hydrocarbon radical having ethylenic unsaturations, so as to avoid any untimely crosslinking of the polycondensate with itself.
According to a particularly preferred embodiment of the present invention, the polysiloxane segment P present in the polycondensates corresponds to formula (Ixe2x80x3) below: 
in which a and z are values as defined above.
As regards, now, the polyurethane and/or polyurea blocks which form a part of the polycondensates used in the context of the invention, these preferably correspond to the general formula (II) below: 
which: in
X2 represents, separately or in combination, xe2x80x94Oxe2x80x94 or xe2x80x94NHxe2x80x94,
R (which, as above for formula (I), is none other than the diisocyanate unit used to carry out the condensation reaction) is as defined above for the blocks of formula (I),
x (which, as indicated above in the description corresponds substantially to the number of moles of couplers used in the process for synthesizing the polycondensate) is an integer which may range from 1 to 10 and preferably from 1 to 3,
and B (which is none other than the unit provided by the coupler as mentioned above) is a divalent hydrocarbon radical bearing a positive or negative ionic charge.
As radicals B bearing anionic groups (i.e. negative charges), mention may be made more particularly of those which bear groups having one or more carboxylic function(s) and/or one or more sulphonic functions, the said carboxylic and/or sulphonic functions being in free form or being partially or totally neutralized with an inorganic or organic base, as will be explained in greater detail hereinbelow.
Thus, among the divalent radicals B bearing carboxylic or sulphonic functions which are particularly suitable in the context of the present invention, mention may be made of those of formula (III): 
which R2 represents a linear or branched C1-C3 alkyl radical, Z represents a carboxylic acid (xe2x80x94COOH) function or sulphonic acid (xe2x80x94SO3H) function or a salt of the said acidic functions (carboxylate and sulphonate functions, respectively), and p and q, which may be identical or different, are integers between 1 and 5, and those of formula (IIIxe2x80x2): 
in which z has the above meaning.
As radicals B bearing cationic groups (i.e. positive charges), mention may be made more particularly of those which bear groups of tertiary amine type, the said tertiary amines being either non-neutralized or partly or totally neutralized (presence of xe2x80x94NH+xe2x80x94 units) or quaternized, as will be explained in greater detail hereinbelow.
Thus, among the divalent radicals B bearing cationizable tertiary amine functions which are particularly suitable in the context of the present invention, mention may be made of those of formula: 
which R3 represents a linear or branched C1-C4 alkyl radical and r and s are both integers, which may be identical or different, which may be between 1 and 10.
In neutralized or quaternized form, the above radicals B then become: 
in which formula R3 has the above meaning, and R4 represents either hydrogen (neutralization) or a linear or branched C1-C10 alkyl radical or an aromatic ring (quaternization).
According to the invention, the degrees of neutralization of the anionizable or cationizable functions may be between 0 and 100%, preferably between 10 and 100%.
The radicals B of the coupler bearing an ionic charge may be used alone or as a mixture with other radicals Bxe2x80x2 originating from couplers not bearing an ionizable group.
Lastly, as regards the radicals R more particularly preferred according to the present invention, which fall within the scope of the definition of the blocks of formulae (I) and (II) given above, mention may be made of those of formulae: 
which b is an integer between 0 and 3 and c is an integer between 1 and 20, preferably between 2 and 12.
Among the particularly preferred divalent radicals R which fall within the scope of the above formulae, mention may be made of hexamethylene, 4,4xe2x80x2-biphenylenemethane, 2,4- and/or 2,6-tolylene, 1,5-naphthylene, p-phenylene and methylene-4,4-bis-cyclohexyl radicals and the divalent radical derived from isophorone.
The process for synthesizing the polycondensates used in the context of the present invention will now be developed in slightly more detail. In these main points, this process corresponds to that already indicated at the start of the description.
An xcex1,xcfx89-dihydroxy and/or diamino and/or amino-hydroxy and/or hydroxyaminopolysiloxane corresponding to the following general formula:
X3xe2x80x94Pxe2x80x94X3
in which P has the meaning given above (polysiloxane segment) and X3 represents, in combination or separately, xe2x80x94OH or xe2x80x94NH2, is reacted, in an organic solvent, with a stoichiometric excess of a diisocyanate of formula:
Oxe2x95x90Cxe2x95x90Nxe2x80x94Rxe2x80x94Nxe2x95x90Cxe2x95x90O
in which R has the meaning given above, followed by coupling the chains of the polycondensate obtained above with at least one diol and/or a diamine and/or an aminoalcohol corresponding to the formula:
X4xe2x80x94Bxe2x80x94X4
in which B has the meaning given above and X4 represents xe2x80x94OH or xe2x80x94NH2, at a temperature of between 40 and 100xc2x0 C., in the presence of a tin salt as catalyst. This diol and/or this diamine X4xe2x80x94Bxe2x80x94X4 may be used alone or as a mixture with one or more diols or diamines or amino alcohols not containing ionizable groups, for example 1,4-butanediol.
The organic solvent used in these steps is preferably chosen from the group consisting of acetone, methyl ethyl ketone, tetrahydrofuran and 1,2-dichloroethane, the solvents being inert towards isocyanate groups.
The tin salt is, itself, preferably chosen from 2-ethyltin hexanoate and dibutyltin dilaurate.
In the context of carrying out the above process, the diisocyanates which are particularly preferred are chosen, alone or as mixtures, from diphenylmethane 4,4xe2x80x2-diisocyanate and methylene-4,4xe2x80x2-dicyclohexyl diisocyanate, and the couplers which are particularly preferred are chosen, alone or as mixtures, from dimethylolpropionic acid, N-methyldiethanolamine, 1,3-diaminopropane and ethanolamine, it being understood that the possibility of mixing acidic coupler/amino coupler is excluded.
The polysiloxane-polyurethane/polyurea polycondensate thus obtained may then optionally be purified, for example by precipitation in a non-polar solvent such as cyclohexane.
In accordance with the invention, this optionally purified polycondensate is then either used in its natural state or neutralized using a suitable neutralizing agent which may be either an inorganic or organic base when the radical B as defined above bears anionizable functions such as, for example, carboxylic and/or sulphonic acid functions, or an inorganic or organic acid when the said radical B bears cationizable functions such as, for example, tertiary amine functions; or quaternized using an alkyl halide, an acidic salt bearing a labile halogen or a sultone (for example propane sultone) when the said radical B bears tertiary amine functions.
According to the invention, the degree of neutralization may range from 0% to 100%, preferably from 10% to 100%.
It goes without saying that the nature of the neutralizing agent which will be suitable for use in neutralizing the polysiloxane-polyurethane/polyurea polycondensate will depend on the nature of the ionizable functions borne by this polycondensate.
When the said polycondensate contains an anionizable function such as, for example, a carboxylic or sulphonic acid function, the neutralizing agent may be an inorganic base such as sodium hydroxide, potassium hydroxide or aqueous ammonia, or an organic base such as an amino alcohol chosen in particular from 2-amino-2-methyl-1-propanol (AMP), triethanolamine, triisopropanolamine (TIPA), monoethanolamine, diethanolamine, tris[(2-hydroxy)-1-propyl]amine, 2-amino-2-methyl-1,3-propanediol (AMPD) and 2-amino-2-hydroxymethyl-1,3-propanediol, or alternatively a diamine such as lysine.
When the polycondensate contains a cationizable function of the tertiary amine type, the neutralizing agent may be an inorganic acid such as hydrochloric acid or an organic acid such as lactic acid, glycolic acid or mandelic acid. The neutralizing agent may also be an agent which quaternizes the tertiary amine function, such as, for example, alkyl halides and in particular methyl iodide or ethyl bromide. It may also be an acid salt bearing a labile halogen or a cyclic sulphonic acid ester.
A solution or an organic solvent-in-water emulsion of the polycondensate in accordance with the invention is then prepared by incorporating it into an organic, aqueous or aqueous-organic solvent system.
The organic solvents for the polycondensates of the invention which are used according to the invention are preferably chosen from acetone, methyl ethyl ketone, methyl acetate, butyl acetate, ethyl acetate, isopropanol, ethanol, dimethoxyethane, diethoxyethane, an ethylene glycol or a propylene glycol ester, an ethylene glycol or a propylene glycol ether, or an ethylene glycol or a propylene glycol ester ether, and mixtures thereof.
Depending on the type of application chosen, it is possible to use, among these solvents for the polycondensates of the invention, a solvent or a mixture of solvents which are miscible with water, one of which (which serves as diluent) evaporates before water so as to allow the polymer to be dissolved in a solvent throughout the drying of the formulation applied to the keratin substance treated. Among the water-miscible solvents, mention may be made of dimethoxyethane and a dimethoxyethane/diethoxyethane mixture. If the formulation envisaged requires the presence of water for the given application, the organic solution of the polymer may, in this case, be diluted in water in order to form an organic solvent-in-water emulsion. This emulsion may be self-stabilized by the ionic charges borne by the polycondensate, which place themselves at the interface with the water, or alternatively stabilized, if necessary, by stabilizers such as surfactants or gelling agents that are present in the aqueous phase.
It is also possible to choose a solvent or a mixture of solvents, for the polycondensates of the invention, that are immiscible with water, such as diethoxyethane. If the formulation envisaged requires the presence of water for the given application, the organic solution of the polymer may, in this case, be dispersed in water in order to form an organic solvent-in-water emulsion. This emulsion may be self-stabilized by the ionic charges borne by the polycondensate, which place themselves at the interface with the water, or stabilized, if necessary, by stabilizers such as surfactants or gelling agents present in the aqueous phase. In this case, the organic solvent or one of the organic solvents used to dissolve the polycondensate preferably has a boiling point higher than that of water. Diethyoxyethane may be used in particular.
A particularly preferred form of solvent system for the polycondensates of the invention consists in using a mixture of solvents of different polarities comprising at least one solvent (A) known as a xe2x80x9cglobalxe2x80x9d solvent for the polycondensate (for the polysiloxane blocks and the polyurethane and/or polyurea blocks) and at least one solvent (B) which is less than polar (A) and which will more specifically dissolve the polysiloxane blocks. In order to promote the stratification of the polysiloxane blocks on the deposition matrix, a solvent (B) whose rate of evaporation is slower than (A) will preferably be chosen.
Among the global solvents (A), mention may be made of acetone, methyl ethyl ketone, methyl acetate, butyl acetate, ethyl acetate, isopropanol, ethanol, dimethoxyethane, diethoxyethane, an ethylene glycol or a propylene glycol ester, an ethylene glycol or a propylene glycol ether, or an ethylene glycol or a propylene glycol ester ether, and mixtures thereof.
Among the solvents (B), mention may be made of hydrocarbons, in particular branched hydrocarbons such as isoparaffins, isodecane and cyclic silicones of the type D4, D5 or D6.
The neutralization may be performed in situ in the solution of the polysiloxane-polyurethane/polyurea polycondensate in the solvent system by adding the determined amount of neutralizing agent.
As indicated above, the cosmetic compositions according to the invention, which thus contain, in a cosmetically acceptable support, polycondensates as defined above, have, for applications as varied as those encountered, for example, in the field of hair care or make-up or alternatively skincare, or in any other cosmetic field in which the use of a film-forming substance is desirable or sought, entirely noteworthy properties, in particular as regards their sheen and film-forming properties, their ability to retain these properties over time in the face of the action of external agents (remanence) and also as regards their properties of softness, lubrication and abrasion-resistance.
Among the applications preferably targeted by the present invention, and the various beneficial effects obtained in these applications, mention may be made more particularly of:
the field of hair products (washing, care or beauty of the hair), where the compositions according to the invention, in particular in aerosol, mousse, shampoo, conditioner, styling or treating lotion or gel, hair shaping or hair setting lacquer or lotion or alternatively fixing form, give the hair sheen, softness, ease of styling (phenomenon of xe2x80x9cindividualizationxe2x80x9d of the hair when the composition is applied), a better feel and remanence (that is to say long-lasting maintenance, even under the action of external agents) of these properties.
The field of make-up products, in particular for making up the nails and the eyelashes, where the compositions according to the invention, in nail varnish, mascara or eyeliner form, for example, afford, in the case of making up the eyelashes, the same advantages as those mentioned above for treating the hair, and, in the case of nail varnishes (where the compositions may be used as sole film-forming agents or as film-forming additive), sheen, better wettability of the nail, remanence of the film and of its sheen on washing, better abrasion-resistance (provision of a sliding effect by lubrication of the surfaces) and better rigidity.
In the field of skincare products (creams, milks, lotions, masks, sera, antisun products), where the compositions according to the invention more particularly afford sheen, better wettability and resistance to washing with water (antisun products).
The proportion of polycondensate in the cosmetic compositions (excluding nail varnishes) is generally between 0.5 and 50% and preferably between 1 and 20% by weight relative to the total weight of the composition. In the case of nail varnishes, this proportion may be up to 30% by weight.
The compositions may also, obviously, contain various adjuvants intended to make them acceptable in a particular cosmetic application.
The compositions according to the invention may contain UV-A or LTW-B or broad-band sunscreens and may thus be used as antisun products.
The compositions according to the invention may moreover contain conventional cosmetic additives chosen from fatty substances, organic solvents, silicones, thickeners, softeners, antifoaming agents, moisturizers, wetting agents, treating agents (agents for combating hair loss, antidandruff agents, etc.), anionic, nonionic or amphoteric polymers or mixtures thereof, antiperspirants, basifying agents, dyes, pigments, fragrances, preserving agents and propellants when the compositions are in aerosol form.
More precisely, an oil or a wax or mixtures thereof, fatty acids, fatty alcohols, fatty acid esters such as triglycerides of C6-C18 fatty acids, petroleum jelly, paraffin, lanolin or hydrogenated or acetylated lanolin may be used as fatty substance.
Among the oils, mention may be made of mineral, animal, plant or synthetic oils and in particular liquid petroleum jelly, liquid paraffin, castor oil, jojoba oil or sesame oil, as well as silicone oils and gums and isoparaffins.
Among the animal, fossil, plant, mineral or synthetic waxes, mention may be made in particular of beeswax, carob wax, candelilla wax, ozocerite, micro-crystalline waxes and silicone waxes and resins.
Among the thickeners, mention may be made of:
modified celluloses such as hydroxyethylcellulose, methylcellulose, hydroxypropylcellulose and carboxy-methylcellulose. Among these, mention may be made in particular of the gums sold under the name xe2x80x9cCellosize QP 44001Hxe2x80x9d by the company Amercol,
carob gum, guar gum, quaternized guar gum, sold under the name xe2x80x9cJaguar C-13-Sxe2x80x9d by the company Meyhall, hydroxypropyl guar gum, xanthan gum,
crosslinked polyacrylic acids such as the xe2x80x9cCarbopolsxe2x80x9d from the company Goodrich,
the polyglyceryl (meth)acrylate polymers sold under the names xe2x80x9cHispagelxe2x80x9d or xe2x80x9cLubragelxe2x80x9d by the companies Hispano Quimica and Guardian,
polyvinylpyrrolidone,
polyvinyl alcohol,
crosslinked acrylamide polymers and copolymers, such as those sold under the names xe2x80x9cPAS 5161xe2x80x9d or xe2x80x9cBozepol Cxe2x80x9d by the company Hoechst, xe2x80x9cSepigel 305xe2x80x9d by the company Seppic or xe2x80x9cSalcare SC95xe2x80x9d by the company Allied Colloid, or alternatively
crosslinked homopolymers of methacrylolyloxy-ethyltrimethylammonium chloride, sold under the name xe2x80x9cSalcare SC95xe2x80x9d by the company Allied Colloid.
Several examples of the preparation of polysiloxane-polyurethane polycondensates and of their solutions or emulsions and of cosmetic compositions containing them will now be given by way of illustration of the invention.
The syntheses leading to the polysiloxane-polyurethane multiblock polycondensates were carried out starting with prepolymers of the xcex1,xcfx89-hydroxyorgano-functional polydimethylsiloxane type (commercial products sold by the company Goldschmidt under the names Tegomer H-Si 2111 and Tegomer H-Si 2311) of structure: 
and also having the characteristics collated in the table below:
These two commercial products will be referred to hereinbelow for convenience as SIL 700 and SIL 2200 (name based on their respective molecular weights).